Merge feat/http-from-mcp: from_mcp adapter (rmcp streamable HTTP, tools/list, structuredContent handling)
Implements FromMCP (feature-gated behind mcp) in src/adapters/from_mcp/: rmcp
StreamableHttpClientTransport connects to MCP endpoint, calls tools/list, builds
HandlerRegistration bundles (provenance FromMCP, leaf, Internal, Mutation,
capabilities=bearer token). Forwarding handler calls client.call_tool, maps
CallToolResult per structuredContent-preferred-over-content-blocks rule (declared
outputSchema → structuredContent; absent → ContentBlock union; no heuristic
JSON.parse; isError→CallError). No-env-vars (reads context.capabilities).
Streamable HTTP only (ADR-037). 19 unit + 5 integration tests.
# Conflicts:
# crates/alknet-http/src/adapters/mod.rs
glm-5.2
3eb2a51184